Automatic fire-spread preventer valve for ventilation ducts

ABSTRACT

A valve device is provided which is intended for preventing the propagation of fire in ventilation ducts or the like. It comprises a valve adapted, in case of abnormal or sufficient temperature increment, to automatically close the duct in which it is mounted.

United States Patent 1 1 Jardinier et al.

1111 3,720,153 1March 13, 1973 AUTOMATIC FIRE-SPREAD PREVENTER VALVE FOR VENTILATION DUCTS Inventors: Pierre Jardinier, Gournay-sur- Marne; Jack Simonnot, Lesigny, both of France Societe dEtudes et de Recherches de Ventilation et dAeraulique, Villiers, sur Marne, France Filed: March 12, 1971 Appl. No; 123,783

Foreign Application Priority Data Assignee:

Mar. 13,1970 France ..700900'1 Us. c1. ..98/86, 49 7, 137/75 Int. Cl. ..Fl6k 13/00, Fl6k 17/40 Field of Search ..49/1, 3, 7, 8, 379; 98/1, 86; 126/2875; 137/72, 73, 74, 75, 76, 77; 160/1, 3; 251/66 [56] References Cited UNITED STATES PATENTS 3,495,606 2/1970 Phillips ..137/75 3,076,469 2/1963 Averill ..137/74 Primary Examiner-Meyer Perlin Assistant ExaminerP. D. Ferguson Attorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A valve device is provided which is intended for preventing the propagation of fire in ventilation ducts or the like. it comprises a valve adapted, in case of abnormal or sufficient temperature increment, to automatically close the duct in which it is mounted.

7 Claims, 4 Drawing Figures AUTOMATIC FIRE-SPREADIZREVENTER VALVE FOR VENTILATION DUCTS l. FIELD OF THE INVENTION The present invention relates to a valve device adapted, in case of sufficient temperature increment, to automatically close a ventilation duct in order to prevent the propagation or spreading of fire therethrough.

2. DESCRIPTION OF THE PRIOR ART As a rule, known valve devices of this character comprise shutter means retained by a fusible element in a position permitting the passage of air through the ventilation ducts equipped therewith. When the temperature increases sufficiently to reduce the resistance of the fusible element,- these shutters are caused to close the passages in these ducts either by gravity or by the action of suitable springs. These devices utilize a movement of translation or a movement of rotation about a fulcrum of said shutters for producing the desired closing action so that they require compulsorily the use of auxiliary means capable of producing the closing movement of the shutters if their operation is to be independent of gravity.

SUMMARY OF THE INVENTION It is the primary object of the present invention to avoid the inconveniences set forth hereinabove by providing a device adapted, in case of abnormal or sufficient temperature increment, to automatically close the air passage in a ventilation duct without resorting to the action of gravity or of any other auxiliary means.

The device according to this invention comprises at least one shutter associated with a seat which, within a range of temperatures having an upper limit, or threshold, is retained by at least one fusible element in a position permitting the passage of an air stream between the shutter and the seat, said shutter, outside said temperature range, being released and caused to engage said seat so as to closethe air passage.

According to this invention, the shutter is cut from a flexible sheet or plate of heat-resistant material and the fusible element retains this shutter in a state of deformation to provide an air passage between the shutter and the seat through a predetermined temperature range; outside this temperature range, the shutter is released and expands soas to automatically engage the aforesaid seat and thus closes completely the initial air passage.

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of this invention will appear as the following description proceeds with reference to the diagrammatic drawings attached hereto, given by way of example only and illustrating a few forms of embodiment thereof. In the drawings:

FIG. 1 is a longitudinal section showing a first embodiment of the invention;

FIG. 2 is another longitudinal section showing a second embodiment of the invention;

FIG. 3 is a similar longitudinal section showing a third embodiment comprising a pair of shutters; and

FIG. 4 illustrates another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, the device illustrated therein comprises a housing 1 of sheet steel, interconnecting two duct sections and having mounted therein in a transverse position a shutter 2 cut from flat spring steel sheet and adapted to be deformed symmetrically in relation to two fastening points 3 of the shutter 2 to said housing 1. A seat 4 rigid with the housing 1 is associated with the shutter 2.

A steel wire 5 having its ends provided with a pair of fusible elements 6 in the form of balls or the like retains the shutter 2 in a state of symmetrical elastic deformation or prestress in relation to the two fastening points This device operates as follows.

As long as the temperature remains below a predetermined threshold or upper limit T, the pair of fusible elements 6 retain the shutter 2 against its natural expansion, as shown in thick lines in FIG. 1, so that air can flow freely through the housing 1 as shown by the arrows 7, i.e. between the walls of said housing and the shutter 2. When the temperature rises above said limit value T, the resistance of fusible elements 6 decreases and eventually cannot prevent the shutter 2 from expanding thus, the shutter assumes the position shown in dash and dot lines in FIG. 1, so as to engage the seat 4 and close completely the air passage 7.

In the embodiment illustrated in FIG. 2, the shape and disposal of the seat 4 are such that the shutter 2 can close the air passage 7 without having to expand fully as in the case illustrated in FIG. 1; under these conditions, the sealing action is more efficient, and the shutter 2 can counteract a possible pressure differential develop ing on either side of the shutter moreover, the shape of seat 4 permits of compensating the effect likely to be produced by a moderate residual deformation of the spring steel which, being prestressed during a relatively long period, might be prevented thereby from resuming a strictly flat configuration when allowed to expand.

The modified device illustrated in FIG. 3 comprises a pair of identical shutters 2a, 2b of spring steel, associated with a corresponding pair of seats 4a, 4b respectively disposed within the same housing '1 interconnecting two aligned duct sections. The shutters 2a,

2b and relevant seats 40, 4b are disposed symmetrically in relation to the rectilinear steel wire 5 having its ends provided with the fusible elements or balls 6.

Below the predetermined temperature threshold, the balls 6 retain the shutters 2a and 2b under the same stress and deformation, in the position shown in thick lines, so that these shutters constitute a substantially streamlined oval obstacle in the fluid flow, as seen in longitudinal section, thus minimizing the drag produced therein, i.e. from one duct section to the other. When the temperature rises to a value beyond said threshold, the shutters expand and engage their seats 4a, 4b respectively, thus preventing the passage of air from one duct section to the other; the expanded shutters 2a, 2b (shown in dash and dot lines will then form with the walls of housing 1, a fluid-tight chamber 8 constituting an efficient heat insulation between the two duct sections interconnected by said housing 1.

It may be noted that, in this specific embodiment comprising a double shutter, the seats may be either of the type shown in FIG. 1 or of the type shown in FIG. 2.

Finally, in the embodiment illustrated in FIG. 4, the shutter 2 is secured along one edge to a fastening point 3 on the inner wall of housing 1, which consists of a frame-like seat 4; the shutter 2, being retained laterally against the inner wall of housing 1, as shown, may be of the twin type as shown in dash and dot lines in the lefthand portion of the figure.

The device according to this invention is adapted to be used notably in case it is desired to prevent a ventilation or air-conditioning duct connected to several different rooms from allowing a fire to spread from one room to another.

Although a few embodiments of the present invention have been described and illustrated herein, it will readily occur to those conversant with the art that various modifications and variations may be brought thereto without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed as new is:

l. A thermal safety device adapted, in case of abnormal and sufficient increment in the temperature in a ventilation or air-conditioning duct, to automatically close said duct and thus prevent the propagation of tire therealong, which comprises a housing adapted to be inserted between two duct sections, a shutter of resilient flexible flat spring-steel material mounted in said housing and, having a free edge portion, said shutter being adapted to flex between an open position allowing flow through said housing and a closed position preventing flow through said housing, a seat in said housing and adapted to be engaged in face-to-face relation by the free edge portion of said shutterwith the latter in closed position, a wire extending through said shutter, and a fusible element on said wire in a position adapted to retain said shutter in its open position by prestressing and bending said shutter whereby, in case of abnormal and sufficient temperature increment in said duct, said fusible element will melt and release said shutter and said edge portion will move into engagement with said seat.

2. Safety device as set forth in claim 1, comprising a second fusible element and means holding said shutter on said housing by two fastening points wherein said shutter in closed position extends transversely in said housing, said shutter being retained in its open position by said fusible elements symmetrically in relation to a plane containing said two fastening points.

3. Safety device as set forth in claim 1, wherein said seat is so disposed in said housing that said shutter edges can engage said seat before expanding completely.

4. Safety device as set forth in claim 2, wherein said fusible elements consist of a pair of balls of a material adapted to melt at said predetermined temperature and each secured to one end of said steel wire.

5. Safety device as set forth in claim 2, wherein said shutter comprises two elements secured to said housing at opposite ends thereof and adapted, in their closed position, to constitute a relatively streamlined oval obstacle in the housing, said shutters being adapted, in their expanded condition, to form a fluid-tight chamber with the walls of said housing.

6. Safety device as set forth in claim 1, comprlsing means by which said shutter is secured along one edge to said housing and in open position lies substantially flatly along said housing.

7. Safety device as set forth in claim 6, wherein said seat comprises a frame-like member secured internally to said housing. 

1. A thermal safety device adapted, in case of abnormal and sufficient increment in the temperature in a ventilation or airconditioning duct, to automatically close said duct and thus prevent the propagation of fire therealong, which comprises a housing adapted to be inserted between two duct sections, a shutter of resilient flexible flat spring-steel material mounted in said housing and, having a free edge portion, said shutter being adapted to flex between an open position allowing flow through said housing and a closed position preventing flow through said housing, a seat in said housing and adapted to be engaged in face-to-face relation by the free edge portion of said shutter with the latter in closed position, a wire extending through said shutter, and a fusible element on said wire in a position adapted to retain said shutter in its open position by prestressing and bending said shutter whereby, in case of abnormal and sufficient temperature increment in said duct, said fusible element will melt and release said shutter and said edge portion will move into engagement with said seat.
 1. A thermal safety device adapted, in case of abnormal and sufficient increment in the temperature in a ventilation or air-conditioning duct, to automatically close said duct and thus prevent the propagation of fire therealong, which comprises a housing adapted to be inserted between two duct sections, a shutter of resilient flexible flat spring-steel material mounted in said housing and, having a free edge portion, said shutter being adapted to flex between an open position allowing flow through said housing and a closed position preventing flow through said housing, a seat in said housing and adapted to be engaged in face-to-face relation by the free edge portion of said shutter with the latter in closed position, a wire extending through said shutter, and a fusible element on said wire in a position adapted to retain said shutter in its open position by prestressing and bending said shutter whereby, in case of abnormal and sufficient temperature increment in said duct, said fusible element will melt and release said shutter and said edge portion will move into engagement with said seat.
 2. Safety device as set forth in claim 1, comprising a second fusible element and means holding said shutter on said housing by two fastening points wherein said shutter in closed position extends transversely in said housing, said shutter being retained in its open position by said fusible elements symmetrically in relation to a plane containing said two fastening points.
 3. Safety device as set forth in claim 1, wherein said seat is so disposed in said housing that said shutter edges can engage said seat before expanding completely.
 4. Safety device as set forth in claim 2, wherein said fusible elements consist of a pair of balls of a material adapted to melt at said predetermined temperature and each secured to one end of said steel wire.
 5. Safety device as set forth in claim 2, wherein said shutter comprises two elements secured to said housing at opposite ends thereof and adapted, in their closed position, to constitute a relatively streamlined oval obstacle in the housing, said shutters being adapted, in their expanded condition, to form a fluid-tight chamber with the walls of said housing.
 6. Safety device as set forth in claim 1, comprising means by which said shutter is secured along one edge to said housing and in open position lies substantially flatly along said housing. 